Pgc 1α

ASCs were grown in 100 mm cell dishes (Corning Glass Works, Corning, NY, USA). After reaching 70–80% confluence, the ASCs were transiently transfected with 1 μg pcDNA-PGC-1α. The PGC-1α plasmid was purchased from OriGene Technologies (Rockville, MD, USA). After 24 h, 1.0 × 10⁶ ASCs were cultured in 5 mL serum-free low-glucose DMEM for 24 h. Therefore, to obtain 0.2 mL of secretome from 1.0 × 10⁶ ASCs, the conditioned media were concentrated 25-fold using ultra filtration units with a 3-kDa molecular weight cutoff (Amicon Ultra-PL 3; Millipore, Bedford, MA, USA). We then injected 0.1 mL of secretome per mouse. This means that one mouse was injected with the secretome obtained from 5 × 10⁵ ASCs. In this study, normal secretome refers to the secretome obtained from empty vector-transfected ASCs, and PGC-secretome refers to the secretome obtained from pcDNA-PGC-1 α transfected ASCs.

Antibodies list: CPT1A (A5307, ABclonal, Wuhan, China), UCP1 (A5857, ABclonal), UCP3(A16996, ABclonal), PPARα (sc-9000, Santa Cruz, Dallas, TX, USA), PPARγ (2435S, CST, Danvers, MA, USA), FAS (3189S, CST), SREBP1 (Sc13551, Santa Cruz), PGC-1α (TA319007, Origene, Rockville, MD, USA), NDUFS3 (459130, Invitrogen, Waltham, MA, USA), SDHB (459230, Invitrogen), UQCRC1 (459140, Invitrogen), COX4 (459600, Invitrogen), ATP Synthase Subunit Alpha (459240, Invitrogen), SOD2 (sc-137254, Santa Cruz), β-Actin (3700S, CST), α-Tubulin (3873S, CST).
Mice diet was provided by SLAC Laboratory Animal Co. Ltd. (Shanghai, China). Insulin was purchased from Nove Nordisk A/S. The blood glucose meter and blood glucose test strip were both purchased from ROCHE (ACCU-CHEK Active).
The Reverse Transcription System kit was purchased from Promega; SYBR green was purchased from Takara; polymerase chain reaction (PCR) primers were synthesized by Beijing Qingke biotechnology Co. Ltd. Nitrocellulose membranes used in W.B. were purchased from PerkinElmer Life Sciences. Other reagents used in this study were purchased from Sigma (St. Louis, MO, USA).

After the treatments, whole proteins were obtained by lysing cells or skin tissues with ice-cold IP lysis buffer (Beyotime, Shanghai, China) plus phenylmethanesulfonylfluoride (PMSF). Equal aliquots (10 μg for cells or 20 μg for tissues) of the protein samples were separated using 8–12% SDS-PAGE, transferred to nitrocellulose membranes (PerkinElmer Life Sciences, Waltham, MA, USA), and blocked with 5% nonfat milk in 1× TBST buffer for 1 h. The membranes were incubated with primary antibodies at 4 °C overnight. After three 1× TBST washing procedures (lasting 10 min), the membranes were incubated with horseradish-peroxidase-conjugated secondary antibodies (1:3000) for 1 h at room temperature. Chemiluminescence was achieved using an ECL Western blotting detection kit (Pierce, Rockford, IL, USA), and the results were quantified using ImageJ (National Institutes of Health, Bethesda, MD, USA). The primary antibodies used included NF-κB (1:1000, CST, Boston, MA, USA), p-NF-κB (1:1000, CST, Boston, MA, USA), SIRT1 (1:1000, CST, Boston, MA, USA), STING (1:1000, ABclonal Technology, Wuhan, China), PGC-1α (1:1000, OriGene Technology, Rockville, MD, USA), and GAPDH (1:5000, Sigma-Aldrich, St. Louis, MO, USA).